JVM Access Operator

Basic Usage

In MCFPP, you can use the :: operator to access the Java object of a variable in the compiler.

int i = 0;
i::jvm.toString(); # Call the `toString` method of `i`
var qwq = i::jvm.type.build("test"); # Call the `build` method of the `type` object of `i`
# The `build` method returns a variable of type `MCIntConcrete`, so the type of `qwq` is `JavaVar`, and the value is `MCIntConcrete`
int awa = qwq; # The value of `qwq` is automatically converted to an MCFPP variable
print(i + qwq);

Also, you can directly access a static method of a Java static class using ::.

::top.mcfpp.model.function$Function.addCommand(::top.mcfpp.command$Command.build("say hello"))

Note that you should use the fully qualified name.

Command Insertion

In the previous section, we mentioned that you can insert a vanilla command using /. You can use a string template-like syntax to insert members and methods of Java objects into vanilla commands.

int i = 0;
/say ${i}
/say ${i::jvm.toString()}
/scoreboard players get ${i::jvm.name} ${i::jvm.sbObject}

Normally, the content in ${} will automatically call the toString() function after calculation, so there is no need to add .toString() separately. However, if the calculation result is MCFPPValue<*>, which is a determined value, the toString() function of the value will be called. For example, JavaVar is an MCFPPValue<*>. Therefore, the compilation result of the above code is:

say 0
say [int,value=0]
scoreboard players get default_func_main_qwq mcfpp_default